Vitamin D: The Sunshine “Vitamin”

Did you know that you’re a lot more like a plant than you realize? Not because you grow roots, and not because you have leaves or flowers, but because you actually have the ability to make one extremely vital nutrient out of sunlight, everyday. How’s that for cool?

The nutrient I’m talking about is called a “vitamin,” but it’s actually closer in structure and function to a hormone—it’s main jobs are to help you absorb calcium for strong bones and to boost your immune system to fight off illness.

It’s nicknamed the “sunshine vitamin” because our skin produces it when we’re exposed to UVB rays. When sunlight hits your skin, the UVB rays turn a type of cholesterol into vitamin D (just another reason we should get comfortable with the idea that we need cholesterol in our lives and in our bodies).

Why is Vitamin D Important?

Let’s start with the one you probably know…

Vitamin D is important for a lot of reasons, but the most publicity it gets is for it’s ability to increase calcium absorption and promote healthy bones.That’s why you see so many dairy products being “fortified” with vitamin D, but don’t be fooled into thinking that dairy is the best source of calcium for you.

Check out the list at the end of this article for great Paleo-friendly and non-dairy food sources of vitamin D.

Fun fact: vitamin D was discovered in 1922 when it was fed to dogs and helped cure them of rickets, a disorder that results in deformed and weakened or “rubbery” bones when vitamin D levels are deficient.

But vitamin D does so much more!

This hormone is also proving to have helpful applications in other areas of our lives—it’s been correlated with decreased risk of cancer. This is due to its effect as an antioxidant as well as its ability to decrease cell proliferation. That basically means that it stops cells from dividing rapidly, which is a hallmark of how cancer cells spread so quickly.

Vitamin D is linked to improvements in symptoms of depression, as well as in autoimmune conditions like multiple sclerosis, rheumatoid arthritis, and even type 1 diabetes. And in a well-known study on heart health, those with higher vitamin D levels had a 60% lower risk of heart disease than those with low levels of vitamin D. More subtle signs of vitamin D deficiency are muscle weakness and bone pain. To put it another way, low levels of vitamin D were correlated with all of the disorders mentioned above.

How to Get Your Daily Dose of Vitamin D

Because vitamin D is found in only a few foods, it’s a good idea to supplement with it if you don’t get at least 15 minutes of sun exposure daily.

The best form of vitamin D to supplement with is vitamin D3.

It was thought for many decades that the other commonly found form of vitamin D, vitamin D2, was equally effective at helping maintain healthy vitamin D levels. However, recent studies have shown that vitamin D2 is less than ⅓ as potent as D3, and the blood levels of supplemental D2 last only a short period of time compared to D3.

Unfortunately, about 50% of the global population is at risk for vitamin D deficiency. In fact, about 1 billion people are listed as being deficient!

Factors that increase your risk of vitamin D deficiency:

Reduced outdoor activities – We get far less exposure to sunlight in our modern society because we’re inside much more than we used to be. This reduces our UVB exposure, meaning we make less vitamin D.

Air pollution blocking sunlight – this also reduces our UVB exposure.

Wearing sunscreen – Wearing a sunscreen of SPF 30 or above can reduce vitamin D synthesis by up to 95%. Instead of always wearing sunscreen, allow yourself 10-20 minutes a day of direct sun exposure. The amount of time you’ll need to produce vitamin D varies depending on how dark your skin tone is, but the Vitamin D Council has a great article helping you understand how to calculate your needs, check it out here.

Having darker skin – Those with darker skin absorb more UVB in the melanin of their skin (increased levels of melanin protects their skin from UV rays), so they need more sunlight exposure to produce sufficient vitamin D. A darker skinned person may require 3-5 times more sun exposure to produce the same amount of vitamin D as a light skinned person.

Eating a low fat diet – Vitamin D is fat soluble, which means it needs dietary fat to be present in order to be used by the body. Those who eat a low-fat diet, or who have a fat malabsorption condition (including some forms of liver disease, cystic fibrosis, and Crohn’s disease, or those who have undergone gastric bypass surgery) are less able to synthesize vitamin D and therefore are at a higher risk for deficiency.

If you think you may be at risk of vitamin D deficiency, you can always opt to get a blood test done to confirm your suspicions one way or the other. On the other hand, with vitamin D deficiency is pretty common these days, so it’s not a terrible idea to experiment with supplementing on occasion.

Recommended supplement dosage to prevent deficiency:

200-600 IU/ daily for ages 19-50

400-600 IU/ daily for ages 51-70

Some researchers agree that it’s safe to take up to 1,000-2,000 IU of vitamin D a day, but if you’re not sure how deficient you are this may lead to vitamin D toxicity. This happens because vitamin D is stored in your fat cells and the body does not flush it out when you supplement with too much. Naturally occurring vitamin D from sun exposure does not reach toxic levels because this excess vitamin D is destroyed by sunlight.

Foods containing vitamin D

It’s still a good idea to include plenty of vitamin D-containing foods in your diet though. Remember that your body needs healthy fats to be able to process vitamin D, so be sure in include those, too. Good choices for vitamin D rich foods are:

Salmon

Sardines

Mackerel

Tuna

Cod liver oil

Shiitake mushrooms

Egg yolk

If you’re not already taking a vitamin D supplement, I’m sure you can see just how important it is now! If you’re taking any type of multivitamin, be sure to check the vitamin D it contains before adding another supplement.